General humidity sensors in the market can be bulky devices. Polymer films such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) are known humidity sensitive layers that are also printable. However, such polymers are generally not sensitive enough to measure humidity using a low voltage power source typically found in wireless devices. Polyelectrolytes such as polystyrenesulfonic acid (PSSA), polyethylene oxide or polyaniline are also known humidity sensitive materials, but they are not soluble in typical solvents.
Techniques for polymerizing aniline with a water soluble polymer as a template have been developed to obtain water-soluble aniline copolymers. However, such copolymerization can adversely affect the sensitivity of the copolymer to water or humidity.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.